Field work … Speed of Light, an installation at Arthur's Seat in Edinburgh. Photograph: Murdo Macleod

Because of the delay in launching last month's assignment, and the high standard of entries we're still receiving, we've decided to run the current "framing a subject" assignment for the next few weeks, until Friday 26 October. In the mean time we have another project for you to work on.

We're launching a competition to find a cover image for the Guardian's forthcoming guide to photography, which will be given away with the paper in November – and we'd like you to get involved.

We'd like you to come up with three images around the theme of "the magic of photography". The judges will be looking for originality as well as a visually stunning image, and we'd like you to be as creative as possible. Ask yourself what makes an image extraordinary. Is it technique (shutter speed, depth of field, multiple exposures, macro etc)? Is it the "decisive moment", in which light, colour and composition come together for a fleeting instant? Any techniques that you use should be achieved at the time of shooting rather than at a later date in Photoshop: we're not looking for manipulated images. The usual Guardian style rules apply, so darkroom techniques only in post-production please (burning in, dodging or cropping).

ContentsThe guide will appear with the Saturday Guardian on 17 November. Inside, you'll find inspiration and advice from a cast of acclaimed Guardian and Observer photographers including Tom Jenkins, Suki Dhanda, Alicia Canter, Katherine Rose, Martin Argles, Eamonn McCabe, Antonio Olmos and Dan Chung. The great war photographer Don McCullin introduces the guide and a host of industry insiders contribute their thoughts on what makes an image powerful.

FormatThe guide will be vertical A5 format, so we need the picture to be a vertical (portrait) shape. Horizontal (landscape) formats will not qualify. The title of the guide is "Photography: A Guardian Masterclass". These words will be overlaid on a part of your image by us, so remember to leave space for text when you're shooting.

Judging processEntries will be judged by a panel on originality, technical proficiency and visual impact. We will create an online gallery of some of the images in the week prior to the guide's publication. The winner will be revealed when the guide is published on Saturday 17 November.

How to enterTo enter, please email a maximum of three high-res images (at 300 dpi) as separate emails to camera.club@theguardian.com with "Photography: A Guardian Masterclass cover competition" in the subject field. You won't be able to use Flickr to submit the images for this competition. All submissions must be your own work. Please include your contact details and a brief description of your submission. The deadline is midnight on Sunday 21 October. For terms and conditions please go to http://www.theguardian.com/artanddesign/2012/oct/05/photography-competition